yes, my car also did the sputtering between 2500-4000rpm and just had nothing there. missing and dieing and what not. well i believe i fixed the problem once and for all. i hooked up my safc and got everything working properly. no settings were changed. i also hooked up my 02 sensor just incase. i decided to watch the 02 sensor while it did this to see if i noticed anything wrong. sure enough, 02 sensor is giving a voltage of .7ish from 2500-3900 or so, and then comes up to .9-.94. well i went through the settings. set my hi throttle points from 2500-4000 about 5% more, .8 now, kept working it up, and eventually got the .9-.94 voltage. no sputtering! the reason mine was sputtering was because it was not getting enough fuel. so if someone is getting the same problem, i would first off recommend getting an air/fuel ratio monitor and see what that looks like, then get safc if it is off. peace

anymore hesitation or sputtering issues, try this ^^^^^^